Rephrasing CONTRIBUTING re: branch for PRs
Making API doc links point at release version
Merge pull request #769 from hflynn/rebased/develop/release-api-links

Making API doc links point at release version (rebased onto develop)
Merge pull request #768 from hflynn/rebased/develop/CONTRIB-update

Rephrasing CONTRIBUTING re: branch for PRs (rebased onto develop)